This invention relates to a sole structure for an athletic shoe, especially for a spiked shoe such as a soccer shoe, a baseball shoe, a golf shoe, or the like.
A prior art sole structure of an athletic shoe for use in various sports is shown in Japanese patent application laying-open publication No. 11-203. This sole structure includes an upper midsole and a lower midsole both of which are generally formed of soft elastic materials, a corrugated sheet interposed between the upper and lower midsoles, and an outsole disposed under the lower surface of the lower midsole and directly contacting the ground.
In such a shoe, due to the corrugated sheet interposed in the heel portion of the midsole, a resistant force tends to occur that restrains the heel portion of the midsole from deforming transversely at the time of contacting the ground, which prevents the heel region of the shoe from slanting sideways and thus, running stability is secured.
The prior art sole structure, however, is comprised of four layers including an upper midsole, a lower midsole, a corrugated sheet, and an outsole, thereby making the weight of the whole sole structure heavier and making the assembly process rather complicated, and an extra cost of a mold becomes necessary.
An object of the present invention is to provide a sole structure for an athletic shoe that secures running stability, decreases weight, simplifies a manufacturing process, and reduces cost. Another object of the present invention is to control flexibility or bendability of an outsole or an outsole body of a shoe structure. A still another object of the current invention is to regulate an upper force applied to an outsole or an outsole body from the ground.
In one embodiment, the sole structure includes a midsole and an outsole located under the midsole and formed of a harder material than the midsole. The midsole is disposed at least at a heel region of a shoe and the midsole heel portion is formed with corrugation at a lower surface thereof at least either on a medial or on a lateral side. The outsole includes an outsole heel portion having corrugation corresponding to the corrugation of the midsole heel portion and an outsole forefoot portion extending from or formed integrally with the outsole heel portion.
Owing to the corrugation or wavy configuration formed at each contact surface between the outsole and the midsole, a resistant force occurs that restrains the midsole heel portion from deforming laterally at the time of contacting the ground, thereby preventing the heel region of the shoe from slanting sideways and securing running stability. Moreover, a two-layer-sole structure with the midsole and the outsole reduces the number of components of the sole structure, decreases the weight of the whole sole structure, simplifies a manufacturing process, and reduces a cost of molds. Furthermore, since the sole structure can be made thinner than a prior art structure, bendability or flexibility of the sole is improved.
The outsole forefoot and heel portions may be formed of the same material or a different material. The midsole may be extended from the heel region to the forefoot region of the shoe. In this case, cushioning properties are ensured along the whole length of the shoe. The wavy configuration of the outsole heel portion may be formed consecutively and laterally between a medial side and a lateral side of the outsole heel portion. In this case, lateral slanting of the heel region of the shoe is more securely prevented. The outsole forefoot portion may also be formed with corrugation. Thus, lateral slanting of the forefoot region of the shoe as well can be prevented.
In a second embodiment, a plurality of plastic or metallic cleats or spikes are provided under the outsole. The sole structure of this embodiment may be applied to a spiked shoe, such as a soccer shoe, a baseball shoe, a golf shoe, a track shoe, or the like. Preferably, the cleats are adapted to control bendability or flexibility of the outsole and to control an upper force applied to the outsole from the ground. The cleats may be located at a crest or a trough of the corrugation of the outsole. Here, the term xe2x80x9ccrestxe2x80x9d and xe2x80x9ctroughxe2x80x9d are interpreted in FIG. 7, which is a side enlarged view of the sole structure. As shown in FIG. 7, a convex portion on the uppers side away from the ground is a crest whereas a convex portion on the ground side is a trough.
In this case, flexibility of the outsole is prevented from being hindered. Specifically, when the cleats are provided at a trough of the corrugation of the outsole, the upper force applied to the cleats from the ground is transmitted to the adjacent crests disposed on both sides of the trough, and thus, the upper force is dispersed and relieved.
The cleats may be disposed between a crest and the adjacent crest or a trough and the adjacent trough of the corrugation of the outsole. In this case, the upper force applied to the cleats from the ground is effectively relieved by the corrugation of the outsole and flexibility of the outsole is restrained. For example, when the cleats are located between a trough and the adjacent trough of the corrugation of the outsole, the upper force from the ground is dispersed and absorbed by the both troughs.
The heel portion of the midsole may have a corrugated sheet or wavy plate therein. In this case, lateral leaning of the heel region of the shoe is further securely prevented.
In a third embodiment, the sole structure includes a midsole body, an outsole body disposed under the midsole body and formed of a harder material than the midsole body, a lower midsole disposed under the heel portion of the outsole body, and an outsole heel portion attached under the lower midsole. The midsole body and the outsole body extend from the heel region to the forefoot region of the shoe. The outsole body has corrugation at least at the heel portion thereof.
In this embodiment, the corrugation formed at the heel portion causes a resistant force that prevents the heel portion of the midsole body from deforming laterally at the time of contacting the ground, thereby preventing the heel region of the shoe from slanting sideways and thus, securing a running stability. Moreover, in this case, the forefoot region of the shoe has a double-layer-sole structure with the midsole body and the outsole body, which reduces the number of shoe components, decreases the weight of the shoe, simplifies a manufacturing process, and reduces a manufacturing cost. Furthermore, since the sole structure can be made thinner as compared with the prior art structure, bendability or flexibility of the forefoot region of the shoe is advanced. The outsole body may have corrugation at a forefoot portion thereof. In this case, lateral leaning of the forefoot region of the shoe can also be prevented.
In a fourth embodiment, a plurality of cleats are provided under the outsole body. The sole structure of this embodiment may be applied to a spiked shoe, such as a soccer shoe, a baseball shoe, a golf shoe, a track shoe, or the like. The cleats are preferably adapted to control bendability or flexibility of the outsole body and to control an upper force applied to the outsole body from the ground. The cleats may be located at a crest or a trough of the corrugation of the outsole body. In this case, bendability or flexibility of the outsole body can be restrained from being hindered. Specifically, when the cleats are provided at a trough of the corrugation of the outsole body, the upper force applied to the cleats from the ground is dispersed and relieved by the adjacent crests. Alternatively, the cleats may be disposed between the adjacent crests or troughs of the corrugation of the outsole body. In this case, the upper force applied to the cleats from the ground is effectively relieved by the corrugation of the outsole body and the flexibility of the outsole is restrained.